In a known method of mixing farinaceous material a rotor is rotated at high speed in the material. The rotor may comprise two extents of bar which are connected together at either end along the rotational axis but diverge away from each other in an arc between those connections. The bars are circular in cross-section. Accordingly when the rotor rotates the material around the rotor is moved slightly in the direction of rotation but little mixing is achieved. Thus the material takes a considerable time to develop and different parts of the mixture may have different temperatures as, particularly with the mixture on the outside of the rotor, the mixing is not complete or rapid enough.